Rocky Mountain National Park. Five visitor centers have books and maps. Campsites at Glacier Basin and Moraine Park can be reserved (from $20; reservations.nps.gov or 800/365-2267); those at Aspenglen, Longs Peak, and Timber Creek are first come, first served (arrive early on weekends). $20 per vehicle (for seven days). www.nps.gov/romo or 970/586-1206.

Hi Country Stables. Guided horseback rides in Rocky Mountain National Park. From $40 per person for two hours. Two locations: Glacier Creek (970/586-3244) and Moraine Park (970/586-2327).

Maroon Bells-Snowmass Wilderness Area. 100 miles of trails and dozens of peaks (including Castle) in Gunnison and White River National Forests. Free wilderness permit required to hike Maroon Bells; available from U.S. Forest Service (806 W. Hallam Ave., Aspen; 970/925-3445) and at trailheads.